So I just turned my old Lenovo Z580 into a Android Build Server. And the first problem I faced was that of making it auto connect to the home Wifi everytime I turn it on.
Basically we have to edit the file
/etc/network/interfaces and make the contents somewhat like this -
auto wlan0 iface wlan0 inet dhcp wpa-ssid YOUR_WIFI_SSID wpa-psk YOUR_WIFI_PASSWORD
This is assuming you are on a WPA/WPA2 PSK encryption. If you are on WEP, why dear why ? Move to WPA.
If you want to affix a permanent static ip address to your server, the contents should rather be like this
auto wlan0 iface wlan0 inet static address 192.168.1.111 netmask 255.255.255.0 gateway 192.168.1.1 wpa-ssid YOUR_WIFI_SSID wpa-psk YOUR_WIFI_PASSWORD
This is assuming your router's ip is
192.168.1.1, and the ip you want to affix the server is
192.168.1.111. Change them to suit your needs.